1. Field of the Invention
This invention relates to formulations of pharmacologically active mixtures of D, L, propranolol and D-propranolol individually. The chemical structure of propranolol, L-(methylethyl)amino!-3-(1-naphthalenyloxy)-2-propanol is as follows: ##STR1##
Propranolol has been commercially available for some time. It is commonly used in the treatment of hypertension, angina and arrhythmias.
2. Description of the Prior Art
.alpha. and .beta. receptors, known as adrenoreceptors, were discovered in 1948. The .beta. receptors are most sensitive to isoprenaline, less to epiniphrine and least to norepinephrine.
Propranolol is a well known .beta. adrenoreceptor blocking agent, known as a .beta.-blocker, and has the aforementioned therapeutic activities. The D and L isomers have distinct activities. The D form is known to have .beta. blocker and antioxidant activities as reported by Mak et al. in Free Radicals, Lipoprotein Oxidation and Artheriosclerosis (1993) Richilieu Press, London. The D configuration is known to have antioxidant activities. Administration of .beta. blockers may lead to harmful side effects. The acceptable dosage level of .beta. blockers may be unpredictable with individual patients and vary widely from one patient to another.
According to the Mak et al. Pharm. Res. Vol. 25., No. 1 (1992) the antioxidant properties of the .beta. blockers may have beneficial effects in the conditions commonly treated with .beta. blockers. Commercially available propranolol, sold under many trademarks, for example INDERAL by Merck & Company, Rahwah, N.J., contains a mixture of 50% D and 50% L propranolol. Forms of pure D and pure L propranolol are not commercially available.
There is a need for a composition with both antioxidant activity and .beta. blocking activity to provide better treatment for those conditions currently being treated by .beta. blockers and for additional indications.